High BMI? What it means for your child, and what you can do about it

In an exclusive post published on Shine today, First Lady Michelle Obama offers some advice, drawn from her own experience, about the Affordable Care Act and how parents can get the most out of visits to the pediatrician. One of her suggestions: Learn about your child’s BMI.
The First Lady was surprised to learn that her daughters’ BMI numbers were “creeping upwards.” “I didn’t really know what BMI was,” she writes. “And I certainly didn’t know that even a small increase in BMI can have serious consequence

s for a child’s health. But as Dr. Susan J. Woolford explains, despite the medical jargon, BMI (Body Mass Index) is actually a very easy way to answer a very difficult question: Is my child overweight?

“We’re concerned about obesity because of the complications of obesity,” Woolford says. “Increased risk for developing problems such as high blood pressure, diabetes, liver disease—all the things that can happen as a result of having a high BMI.”

The medical director of the Pediatric Comprehensive Weight Management Center at the University of Michigan, Woolford says that it’s not practical to directly measure each and every child’s body fat. “So the BMI is a good way of getting a sense of that, because we compare weight to height and it gives us a sense of whether a person’s weight is too much for their height.”

The U.S. Centers for Disease Control and Prevention and the American Academy for Pediatrics recommend that pediatricians start screening children around age 2. Because boys and girls have different amounts of body fat, and because the amount of fat on a healthy kid changes as they age, there are different charts for evaluating BMI results based on age and gender. According to the CDC, if a child’s BMI falls in the 85th to 94th percentile for his or her age and weight—meaning that the child’s BMI is higher than 85 to 94 percent of other children in the same age and weight categories—the child is considered overweight. Anything in the 95th percentile or above is considered obese. A healthy BMI is one that’s between the 5th and 84th percentiles; less than 5th percentile means that the child is underweight.

Body Mass Index doesn’t directly measure body fat—it’s a screening tool, not a diagnostic tool, Woolford points out. And BMI isn’t always accurate; since muscle weighs more than fat, most athletes, even as children, may be considered overweight or even obese when looking at their BMI numbers alone. “But for the majority of Americans, that’s not what we find,” Woolford points out. “For the vast majority of Americans, when weight is too high for height it’s because we’re dealing with adiposity,” or an overabundance of fatty tissue.

If a parent learns, as the Obamas did, that their child’s BMI is getting too high, the best thing to do is to speak with the child’s primary care physician to determine how at-risk the child is for obesity and obesity-related complications. If the parent and pediatrician decide that there is something to be concerned about, there are plenty of simple ways parents can address the problem.

“One of the most important things that can be done is to model a healthy lifestyle for the chid,” says Woolford. “I don’t think it works terribly well to just identify that this child has a problem and identify changes we’ll make in the child’s diet alone or their exercise habits alone. It’s much more successful if the entire family makes the changes, and if the parents model healthy lifestyle practices.”

Those practices should include increasing exercise, decreasing sedentary activities like watching TV and playing video games, and changing eating habits.

P.K. Newby, a nutrition scientist who is an associate professor and research scientist in the Department of Pediatrics at the Boston University School of Medicine and the Department of Epidemiology at the Boston University School of Public Health says that cutting back on sugar-sweetened beverages like sodas and juice-like drinks is a good place to start. “It’s really a source of empty calories and sugars,” she points out. Water is a better alternative, she suggests.

Parents should also be careful about portion sizes, something that’s easier to do at home than in a restaurant or cafeteria. “If you’re eating a lot outside of the home where you’re not as able to control the portion sizes, that’s going to lead to excess caloric intake,” she says.

Newby, who has done extensive research into dietary patterns, plant-based diets, and obesity, says, “The more plant-based the diet is, the better, for kids as well as the environment.”

“Having plant foods and whole foods being the center of the plate, rather than the meat, is really the best way to go here,” Newby says. “That means vegetables, whole grains, fruits, and minimally processed foods.” Whole foods (think fruits and vegetables) have a greater nutritional benefit than foods that have been highly refined. “Whole foods are higher in fiber, higher in water, lower in total fat, and lower in calories,” she explains. “Shifting your plate toward those types of foods will help kids and adults maintain healthy weight.”

Snack time is an excellent time to offer fruits and vegetables as opposed to typical snack foods, which tend to be highly processed. “Another good piece of advice, I think, is to not keep your high-sugar, high-fat, processed snacks in the house,” she says. “Keep them as treats, otherwise they may be too tempting.”